This invention relates to nucleic acid and amino acid sequences of a cyclophilin-type peptidyl-prolyl cis/trans isomerase and to the use of these sequences in the diagnosis, treatment, and prevention of cancer, autoimmune/inflammatory disorders, and reproductive disorders.
Numerous essential biochemical reactions involve the isomerization of a substrate. Enzymes which catalyze such reactions are known as isomerases. A number of isomerases have been described catalyzing steps in a wide variety of biochemical pathways including protein folding, phototransduction, and various anabolic and catabolic pathways in organisms ranging from bacteria to humans.
One class of isomerases is known as peptidyl-prolyl cis-trans isomerases (PPIases). PPIases catalyze the cis to trans isomerization of certain proline imidic bonds in proteins. Two families of PPIases are the FK506 binding proteins (FKBP), and cyclophilins (CyPs). FKBPs bind the potent immunosuppressants, FK506 and rapamycin, thereby inhibiting signaling pathways in T-cells. Specifically, the PPIase activity of FKBPs is inhibited by binding of FK506 or rapamycin. There are five members of the FKBP family which are named according to their calculated molecular masses (FKBP12, FKBP13, FKBP25, FKBP52, and FKBP65), and localized to different regions of the cell where they associate with different protein complexes (Coss, M. et al. (1995) J. Biol. Chem. 270:29336-29341; Schreiber, S. L. (1991) Science 251:283-287).
CyP was originally characterized as the receptor for the immunosuppressant drug cyclosporin, an inhibitor of T-cell activation. Thus, the peptidyl-prolyl isomerase activity of CyP may be part of the signaling pathway that leads to T-cell activation. Subsequent work demonstrated that CyP""s isomerase activity is essential for correct protein folding and/or protein trafficking, and may also be involved in assembly/disassembly of protein complexes and regulation of protein activity. For example, in Drosophila, the CyP NinaA is required for correct localization of rhodopsins, while a mammalian CyP (Cyp40) is part of the Hsp90/Hsc70 complex that binds steroid receptors. The mammalian CypA has been shown to bind the gag protein from human immunodeficiency virus 1 (HIV-1), an interaction that can be inhibited by cyclosporin. Since cyclosporin has potent anti-HIV-1 activity, CypA may play an essential function in HIV-1 replication. Finally, Cyp40 has been shown to bind and inactivate the transcription factor c-Myb, an effect that is reversed by cyclosporin. This effect implicates CyPs in the regulation of transcription, transformation, and differentiation (Bergsma, D. J. et al (1991) J. Biol. Chem. 266:23204-23214; Hunter, T. (1998) Cell 92: 141-143; and Leverson, J. D. and Ness, S. A. (1998) Mol. Cell. 1:203-211).
The discovery of a new cyclophilin-type peptidyl-prolyl cis/trans isomerase and the polynucleotides encoding it satisfies a need in the art by providing new compositions which are useful in the diagnosis, prevention, and treatment of cancer, autoimmune/inflammatory disorders, and reproductive disorders.
The invention is based on the discovery of a new human cyclophilin-type peptidyl-prolyl cis/trans isomerase (CPCI), the polynucleotides encoding CPCI, and the use of these compositions for the diagnosis, treatment, or prevention of cancer, autoimmune/inflammatory disorders, and reproductive disorders.
The invention features a substantially purified polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1.
The invention further provides a substantially purified variant having at least 90% amino acid sequence identity to the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO: 1. The invention also provides an isolated and purified polynucleotide encoding the polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO: 1. The invention also includes an isolated and purified polynucleotide variant having at least 70% polynucleotide sequence identity to the polynucleotide encoding the polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1.
The invention further provides an isolated and purified polynucleotide which hybridizes under stringent conditions to the polynucleotide encoding the polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1, as well as an isolated and purified polynucleotide having a sequence which is complementary to the polynucleotide encoding the polypeptide comprising the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1.
The invention also provides an isolated and purified polynucleotide comprising the polynucleotide sequence of SEQ ID NO:2 or a fragment of SEQ ID NO:2, and an isolated and purified polynucleotide variant having at least 70% polynucleotide sequence identity to the polynucleotide comprising the polynucleotide sequence of SEQ ID NO:2 or a fragment of SEQ ID NO:2. The invention also provides an isolated and purified polynucleotide having a sequence complementary to the polynucleotide comprising the polynucleotide sequence of SEQ ID NO:2 or a fragment of SEQ ID NO:2.
The invention also provides a method for detecting a polynucleotide in a sample containing nucleic acids, the method comprising the steps of (a) hybridizing the complement of the polynucleotide sequence to at least one of the polynucleotides of the sample, thereby forming a hybridization complex; and (b) detecting the hybridization complex, wherein the presence of the hybridization complex correlates with the presence of a polynucleotide in the sample. In one aspect, the method further comprises amplifying the polynucleotide prior to hybridization.
The invention further provides an expression vector containing at least a fragment of the polynucleotide encoding the polypeptide comprising the sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1. In another aspect, the expression vector is contained within a host cell.
The invention also provides a method for producing a polypeptide, the method comprising the steps of: (a) culturing the host cell containing an expression vector containing at least a fragment of a polynucleotide under conditions suitable for the expression of the polypeptide; and (b) recovering the polypeptide from the host cell culture.
The invention also provides a pharmaceutical composition comprising a substantially purified polypeptide having the sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1 in conjunction with a suitable pharmaceutical carrier.
The invention further includes a purified antibody which binds to a polypeptide comprising the sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1, as well as a purified agonist and a purified antagonist of the polypeptide.
The invention also provides a method for treating or preventing a disorder associated with decreased expression or activity of CPCI, the method comprising administering to a subject in need of such treatment an effective amount of a pharmaceutical composition comprising a substantially purified polypeptide having the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1, in conjunction with a suitable pharmaceutical carrier.
The invention also provides a method for treating or preventing a disorder associated with increased expression or activity of CPCI, the method comprising administering to a subject in need of such treatment an effective amount of an antagonist of the polypeptide having the amino acid sequence of SEQ ID NO:1 or a fragment of SEQ ID NO:1.